The technology of information transfer through satellites continues to increase rapidly due to the climbing demand for wireless communication applications. As the demand for wireless communication applications increases, so also does the demand for satellite payload. It is very difficult and very expensive to design and implement single monolithic satellite systems, to integrate the requirements of multiple subsystems and payloads, and to adhere to tight launch constraints. To alleviate this difficulty, a satellite's functionality can be distributed into a group of satellites. By distributing satellite functionality, launch options increase, financial and scheduling constraints become more flexible, the system becomes more modular, and each payload or subsystem can become optimized for a given purpose.
To distribute satellite functionality, the launching of a group of satellites occurs using a specific technique called formation flight. Formation-keeping involves the use of an active control scheme to maintain the relative positions of the spacecraft. It is often very important to keep relative positional control for certain satellite applications, such as radar or optical interferometry. However, formation-keeping puts tight tolerances on the control system, and satellites kept in stationary relative positions are often subject to large drift forces. To compensate for drift, a satellite must expend large amounts of fuel to keep formation over long durations, thus necessitating a large amount of delta-V to maintain operation.